Evaluation of the Possible Neurotoxic Effect of the Bone Cement on the Facial Nerve: An Experimental Study

Migration and other electrode complications following cochlear implantation

OBJECTIVES

To investigate migration and other electrode-related complications in cochlear implant surgery.

METHODS

Retrospective review of all patients (adult and paediatric) undergoing cochlear implantation at a tertiary referral centre in England, between April 2019 and December 2021. Split arrays and patients who did not have post-op imaging were excluded.

RESULTS

Two hundred and ninety-nine cochlear implants were performed including 90% primary and 10% revision surgeries. Two hundred and forty-eight (86%) of electrodes implanted were straight arrays.Twenty-seven (9%) demonstrated suboptimal position on post-operative imaging. Three (11%) were true migration, 4 (15%) possible migration, 15 (56%) had two or less extra-cochlear electrodes, 3 (11%) expected partial insertion and 2 (7%) demonstrated tip fold-overs. Twenty (74%) of arrays within the suboptimal insertion group were in primary surgeries. Six patients required re-implantation. The most common reason for re-implantation was migration.

DISCUSSION

Electrode migration after cochlear implantation may be more common than previously thought. We demonstrate rates of migration congruous with current literature; this is despite robust and varied fixation techniques. Notable in our series is that all true captured migrations were seen exclusively in straight arrays. The majority of patients in the possible and confirmed migration group had normal inner ear anatomy.

CONCLUSION

Suboptimal electrode position following cochlear implant surgery is a recognized complication and can affect implant performance. Reporting may increase with more widespread use of sophisticated post-operative imaging. Use of a pre-curved electrode and routine use of appropriate fixation techniques may reduce migration rates.

Are long-term auditory results following ossiculoplasty with bone cement as successful as early-middle period results?

PURPOSE

Bone-cement (BC) ossiculoplasty is one of the options to solve ossicular chain problems. Many authors reported successful results in the early or mid-follow-up period; however, there is no long-term result in the literature. We aim to evaluate long term results of BC ossiculoplasty.

MATERIALS AND METHODS

Forty-eight patients who underwent BC ossiculoplasty as incudostapedial re-bridging by the same surgeon were invited to evaluation. Postoperative otomicroscopic examination was performed. Pre-operative and post-operative audiological results after longer follow up and graft success rate were noted.

RESULTS

Fourteen patients came for control examination. The follow-up period was between 87 and 135 months (mean 102 months). None of the patients had graft failure. Ten patients had early postoperative follow-up results (between 10 and 52; mean 24 months). In the comparison of preoperative and early postoperative air-bone gap, there were significant differences in all frequencies while the comparison of preoperative and long-term postoperative results showed a significant difference only in 250 and 500 Hz. Early postoperative results were better than late with significant difference only in the 2000 and 4000 Hz.

CONCLUSIONS

As reported by many studies, bone cement application provides a significant auditory improvement in the early postoperative period. The results of the present study showed that this early auditory success may decrease over time with a long-term follow-up. Further studies should be conducted with larger patient groups to clarify the long-term benefits of this treatment and possible causes for its deterioration.